Neural mechanisms underlying vocal learning in the songbird

鸣禽发声学习的神经机制 习得的动作序列是人类大多数交流的基础，但人们对它知之甚少。 神经系统如何学会控制复杂的肌肉动作。我们的长期目标是 描述习得运动行为的神经回路机制。的 斑胸草雀，一种鸣禽，提供了一个独特的系统，在其中追求这一目标，因为它获得了它的歌曲， 就像我们学习包括语言在内的许多运动技能一样。 目的：我们的建议旨在描述如何运动程序的歌曲发展记录从 在自由行为的幼年斑胸草雀中，运动皮层类似结构（RA核）中的神经元 学习歌曲（目标1）RA被广泛认为是发声学习的场所， 来自高阶运动区HVC和基底神经节回路的会聚输入。该提案 将检查这两个输入在RA中形成运动命令的各自作用， 学习（目标2）。我们研究如何听觉反馈为基础的性能评估，一个关键的 一种成分，既为歌曲学习和歌曲维护，影响发展的运动 方案（目标3）。最后，我们评估了学习引起RA运动改变的程度 程序是由HVC的变化驱动的，它的前运动输入（目标4）。 方法：该提案将结合强有力的方法来研究这些问题：自定义- 制造的电动微驱动器将允许记录RA中的单个神经元， 鸟，长期植入反向微透析装置将使快速和可逆的 基底神经节回路的失活。最后，我们将使用数学模型， 观察到一个生物病理学上合理的模型，如何歌曲电路学习和功能。 相关性：我们的实验旨在描述复杂运动背后的运动程序如何 行为的演变，以及运动电路的逻辑基础上，它是组织相对于 学习产生发声的神经回路之间的同源性和相似性， 鸣禽和人类有很多，因此我们的发现也将谈到这个问题， 可以获取作为语音和其它学习的运动行为基础的程序。了解 复杂运动学习的神经相关性将使我们能够确定该过程如何失败， 解决各种运动障碍和残疾的可能原因。

Neural mechanisms underlying vocal learning in the songbird Learned motor sequences underlie most of human communication, yet remarkably little is known about how the nervous system learns to control the complex muscle actions involved. Our long term goal is to describe the neural circuit mechanisms underlying the acquisition of learned motor behaviors. The zebra finch, a songbird, provides a unique system in which to pursue this goal, as it acquires its song in much the same way that we learn many of our motor skills, including speech. Aims: Our proposal aims to describe how the motor program for song develops by recording from neurons in a motor cortex analogue structure (nucleus RA) in the freely behaving, juvenile zebra finch throughout song learning (Aim 1). Widely thought to be the site of vocal learning, RA receives convergent input from a higher order motor area, HVC, and from a basal ganglia circuit. The proposal will examine the respective roles of these two inputs in shaping the motor command in RA during learning (Aim 2). We examine how auditory feedback-based performance evaluation, a crucial ingredient for both song learning and song maintenance, influences the development of the motor program (Aim 3). Lastly, we assess the extent to which the learning induced changes in the RA motor program are driven by changes in HVC, its premotor input (Aim 4). Methods: The proposal will examine these issues with a combination of powerful methods: custom- made motorized microdrives will allow the recording of single neurons in RA in the singing, juvenile bird, and a chronically implanted reverse microdialysis device will make possible the fast and reversible inactivation of the basal ganglia circuit. Finally, we will use mathematical models that incorporate our observations into a biophysically plausible model of how the song circuit learns and functions. Relevance: Our experiments aim to describe how the motor program underlying a complex motor behavior evolves, and the logic by which the motor circuits underlying it are organized with respect to learning. The homologies and analogies between the neural circuits generating vocalizations in songbirds and humans are many, thus our findings will also speak to the question of how the motor program underlying speech and other learned motor behaviors may be acquired. Understanding the neural correlates of complex motor learning will allow us to pinpoint how the process may fail, thus addressing the possible causes of various motor disorders and disabilities.